PURPOSE: To suppress variation in DC potential within a practical use range, to eliminate the need fo adjustment, and to prevent the generation of spotlike disturbance, by switching the difference signals between two modulated signal which contain little DC component, and an amplitude-limited signal.

CONSTITUTION: This dropout compensator consists of the 1st demodulator 8 for demodulating the output signal of the 1st electronic switch 2, the 2nd demodulator 10 for demodulating the output signal of a delay device 6, the 1st subtracting circuit 17 for extracting the difference component between the outputs of the 1st and 2nd demodulators, a filter 18 which cuts off DC components and transmits a specific frequency signal, the 2nd electronic switch 19 having two input terminals 20 and 21 and one output terminal 22, the 2nd delay circuit 23 which generates a signal for controlling the switch 19 without delay during the generation of a dropout and with prescribed-time delay after the completion of the dropout, and the 2nd subtracting circuit which subtracts the output signal of the switch 19 from the output signal of an amplifier 24. Thus, the generation of spotlike disturbance is prevented during the generation and completion of dropout disturbance.